Specs: 2001 Ford Ranger, 2.3L 4cyl, 92K miles, Manual

Problem: Sometimes at acceleration, but mostly once at speed - the engine will sort of 'kick in and out.' Sort of going from positive power to what feels like 3 cylinders all the sudden. Also, the exhaust sort of rattles at idle so that's why I think it might be a bad catalytic converter.

So Far: Plugs/Wires, MAF sensor, TPS Sensor good, Vacuum is Fine

What I think might be the issue: O2 Sensor or a Clogged Catlytic Converter. Mechanic checked it out however, said that the problem wasn't bad enough to find (no codes) and it would have to get worse in order to find a solution.

Any ideas?

Tried to keep it short and sweet . . .

Brandon